In vehicles equipped with fuel cell systems (hereinafter referred to as “fuel cell vehicles”), a plurality of power devices is used in order to supply power from a fuel cell and a power storage device to a motor. A DC-DC converter is a power device that converts a voltage between the fuel cell and an inverter. An inverter is a power device that converts a DC input voltage to an alternating-current voltage and supplies it to a motor. Also, there is a system in which, in addition to the above DC-DC converter, another DC-DC converter is provided between a power storage device and an inverter. In such fuel cell vehicles, power losses are caused in the power devices including the motor, and therefore, reductions in power losses have been demanded.
For example, JP2005-348530 A discloses an invention in which an output voltage value of a fuel cell is set to between the maximum value and the minimum value of a circuit voltage of a power storage device, thereby decreasing the frequency of voltage conversion operations, leading to the suppression of increases in power losses.